Could New FBI DNA Testing Finally Solve the Nancy Guthrie Case? The Nancy Guthrie case may have just reached a turning point. The FBI is now reportedly using advanced SNP DNA analysis on evidence taken from Nancy’s home, a powerful forensic method that could identify an unknown suspect and breathe new life into this haunting cold case. Retired NYPD Sgt. Bill Cannon breaks down how SNP DNA works, why investigators use it, and why this latest move could be the key to finally unlocking the truth. If this testing produces the results investigators hope for, it could mark the most important breakthrough in the Nancy Guthrie investigation in years.